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United States Patent | 5,001,386 |
Sullivan ,   et al. | March 19, 1991 |
A dimming circuit provides power from an ac source to a compact fluorescent lamp. The circuit generally includes a resonant circuit driven by a high-frequency switching inverter. The resonant circuit is essentially an ac current source and provides sinusoidal current to the lamp, which loads the resonant circuit in parallel. A small amount of dc current is simutaneously provided to the lamp. The resultant asymmetric current waveform flowing through the lamp substantially eliminates striation over a dimming range from about 100% to 1% of full light output.
Inventors: | Sullivan; Charles R. (Coopersburg, PA); Jurell; Scott R. (Hellertown, PA); Luchaco; David G. (Macungie, PA) |
Assignee: | Lutron Electronics Co., Inc. (Coopersburg, PA) |
Appl. No.: | 455644 |
Filed: | December 22, 1989 |
Current U.S. Class: | 315/219; 315/166; 315/171; 315/307; 315/DIG.4 |
Intern'l Class: | H05B 041/29; H05B 041/392 |
Field of Search: | 315/166,171,176,219,307,DIG.4,DIG.5,DIG.7 |
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4350935 | Sep., 1982 | Spira et al. | 315/291. |
4651060 | Mar., 1987 | Clark | 315/199. |
4663569 | May., 1987 | Alley et al. | 315/175. |
4663570 | May., 1987 | Luchaco et al. | 315/219. |
4682082 | Jul., 1987 | MacAskill et al. | 315/219. |
4745342 | May., 1988 | Andreson et al. | 315/200. |
4792727 | Dec., 1988 | Godyak | 315/171. |
4853598 | Aug., 1989 | Kusko et al. | 315/101. |
4862042 | Aug., 1989 | Herrick | 315/174. |
4870326 | Sep., 1989 | Andresen et al. | 315/200. |
4916362 | Apr., 1990 | Orenstein | 315/223. |
May & Chrsite GMBH Transformaternwerke brochure. Welding Power handbook, Union Carbide, Manz, A.F., pp. 100-109, 9-1981. Cherry/Gas Plasma Displays brochure, No. CE-023. Luciano DiFraia, "A Method to Achieve Continuous Dimming of Low Pressure Sodium and Other Gas Discharge Lamps", Journal of IES (Jul. 1981), pp. 245-252. |